Some devices include a magnetic assembly having more than one magnetic polarity. This can be done in several ways. Several individual magnets with different polarities can be aligned together to form the magnetic assembly. Alternatively, an electromagnet may be used to apply a magnetic field to a substrate.
However, each method has drawbacks. For instance, aligning several magnets can be time consuming and expensive. Further, to cut the magnets made from relatively hard materials requires a high end blade (e.g., diamond blade) which erodes much of the substrate during the cutting process. Electromagnets may require a relatively high amount of voltage and current, particularly in materials having a high coercivity. This may also increase costs and create a potentially dangerous environment.